1. Field of the Invention
The present invention relates, generally, to an instrument panel for an automotive vehicle and, more specifically, to a system for mounting the instrument panel to the body of the vehicle.
2. Description of the Related Art
An instrument panel, or dashboard, of a motor vehicle is generally mounted to the body of the vehicle using a plurality of brackets and corresponding attachment structures. More specifically, the instrument panel usually includes a cross beam extending along the longitudinal length of the instrument panel. Each of the brackets of the instrument panel is secured to the cross beam at one end of the bracket. The other end of the bracket includes the attachment structure, which is described in detail below. The instrument panel is typically mounted to a panel of the vehicle body known as the “body in white.” The body in white includes a plenum, or cowl panel, extending completely across the vehicle and disposed in spaced, substantially parallel relation with the cross beam. Each bracket extends substantially perpendicular with respect to the cross beam to the plenum. The attachment structure of the other end of each bracket is attached to the plenum to mount the instrument panel to the vehicle body.
In particular, the attachment structure of the instrument panel typically includes a base panel, a steel or sheet-metal structure, and a fastener, such as a bolt or screw. A bolt, for instance, fastens the base panel to the plenum while sandwiching the steel structure between them. The base panel is, therefore, sandwiched between the head of the bolt and the steel structure. In this way, the bolt is adapted to generate a clamping force, or torque, to mount the instrument panel to the vehicle body.
The bolt can exert a magnitude of torque of approximately 120 lbs.+/−20 lbs. upon the base panel of the instrument panel at the plenum. However, the base panel is typically made of thermo-plastic olefin (TPO), which is a rubberized version of polypropylene. TPO is a relatively soft material that does not adequately take torque beyond a magnitude of 20 lbs.+/−5 lbs. More specifically, beyond this magnitude, a continual tightening and relaxing of the base panel can occur within a range of approximately 2 mm, for example. This “squishing” effect can cause the base panel to continually change its shape under the torque of the bolt sufficiently such that it is not adequately secured in its proper position between the bolt head and the steel structure and, thus, becomes loose. As a result, the instrument panel can buzz, squeak, and/or rattle with respect to the vehicle body. In this case, an instrument panel having a TPO base panel will not achieve a proper amount of torque at the plenum where the base panel is sandwiched between the steel structure and the bolt head.
To solve this problem, a brass washer or shoulder bolt is often used to better distribute the clamping force exerted by the bolt. Brass is used for this application because it is strong and, yet, malleable. As such, the torque extends through both the washer, for instance, and base panel. In this way, the base panel is not subjected to such high levels of concentrated clamping force. Thus, the “squishing” effect of the base panel is decreased. The bolt, however, still places a proper amount of torque on the steel structure to capture, but not disturb, the TPO base panel.
Although the instrument-panel attachment structure of the related art is adequate for its intended purpose, it has some disadvantages. In particular, use of brass washers in connection with shoulder bolt adds cost to the manufacture of the respective vehicle. This is especially true in view of the fact that there are typically four brackets used to mount any given instrument panel to the vehicle body, each of which requires a brass-washer-and-bolt combination.
Accordingly, there remains a need in the related art for a cost-effective mounting system that effectively distributes clamping force while securely mounting an instrument panel to a vehicle body. There is also a need in the related art to reduce the number of components employed in any mounting system thereby reducing parts.